gotosocial/vendor/github.com/godbus/dbus/v5/auth.go
Daniele Sluijters acc333c40b
[feature] Inherit resource limits from cgroups (#1336)
When GTS is running in a container runtime which has configured CPU or
memory limits or under an init system that uses cgroups to impose CPU
and memory limits the values the Go runtime sees for GOMAXPROCS and
GOMEMLIMIT are still based on the host resources, not the cgroup.

At least for the throttling middlewares which use GOMAXPROCS to
configure their queue size, this can result in GTS running with values
too big compared to the resources that will actuall be available to it.

This introduces 2 dependencies which can pick up resource contraints
from the current cgroup and tune the Go runtime accordingly. This should
result in the different queues being appropriately sized and in general
more predictable performance. These dependencies are a no-op on
non-Linux systems or if running in a cgroup that doesn't set a limit on
CPU or memory.

The automatic tuning of GOMEMLIMIT can be disabled by either explicitly
setting GOMEMLIMIT yourself or by setting AUTOMEMLIMIT=off. The
automatic tuning of GOMAXPROCS can similarly be counteracted by setting
GOMAXPROCS yourself.
2023-01-17 20:59:04 +00:00

252 lines
6.6 KiB
Go

package dbus
import (
"bufio"
"bytes"
"errors"
"io"
"os"
"strconv"
)
// AuthStatus represents the Status of an authentication mechanism.
type AuthStatus byte
const (
// AuthOk signals that authentication is finished; the next command
// from the server should be an OK.
AuthOk AuthStatus = iota
// AuthContinue signals that additional data is needed; the next command
// from the server should be a DATA.
AuthContinue
// AuthError signals an error; the server sent invalid data or some
// other unexpected thing happened and the current authentication
// process should be aborted.
AuthError
)
type authState byte
const (
waitingForData authState = iota
waitingForOk
waitingForReject
)
// Auth defines the behaviour of an authentication mechanism.
type Auth interface {
// Return the name of the mechanism, the argument to the first AUTH command
// and the next status.
FirstData() (name, resp []byte, status AuthStatus)
// Process the given DATA command, and return the argument to the DATA
// command and the next status. If len(resp) == 0, no DATA command is sent.
HandleData(data []byte) (resp []byte, status AuthStatus)
}
// Auth authenticates the connection, trying the given list of authentication
// mechanisms (in that order). If nil is passed, the EXTERNAL and
// DBUS_COOKIE_SHA1 mechanisms are tried for the current user. For private
// connections, this method must be called before sending any messages to the
// bus. Auth must not be called on shared connections.
func (conn *Conn) Auth(methods []Auth) error {
if methods == nil {
uid := strconv.Itoa(os.Getuid())
methods = []Auth{AuthExternal(uid), AuthCookieSha1(uid, getHomeDir())}
}
in := bufio.NewReader(conn.transport)
err := conn.transport.SendNullByte()
if err != nil {
return err
}
err = authWriteLine(conn.transport, []byte("AUTH"))
if err != nil {
return err
}
s, err := authReadLine(in)
if err != nil {
return err
}
if len(s) < 2 || !bytes.Equal(s[0], []byte("REJECTED")) {
return errors.New("dbus: authentication protocol error")
}
s = s[1:]
for _, v := range s {
for _, m := range methods {
if name, data, status := m.FirstData(); bytes.Equal(v, name) {
var ok bool
err = authWriteLine(conn.transport, []byte("AUTH"), v, data)
if err != nil {
return err
}
switch status {
case AuthOk:
err, ok = conn.tryAuth(m, waitingForOk, in)
case AuthContinue:
err, ok = conn.tryAuth(m, waitingForData, in)
default:
panic("dbus: invalid authentication status")
}
if err != nil {
return err
}
if ok {
if conn.transport.SupportsUnixFDs() {
err = authWriteLine(conn, []byte("NEGOTIATE_UNIX_FD"))
if err != nil {
return err
}
line, err := authReadLine(in)
if err != nil {
return err
}
switch {
case bytes.Equal(line[0], []byte("AGREE_UNIX_FD")):
conn.EnableUnixFDs()
conn.unixFD = true
case bytes.Equal(line[0], []byte("ERROR")):
default:
return errors.New("dbus: authentication protocol error")
}
}
err = authWriteLine(conn.transport, []byte("BEGIN"))
if err != nil {
return err
}
go conn.inWorker()
return nil
}
}
}
}
return errors.New("dbus: authentication failed")
}
// tryAuth tries to authenticate with m as the mechanism, using state as the
// initial authState and in for reading input. It returns (nil, true) on
// success, (nil, false) on a REJECTED and (someErr, false) if some other
// error occurred.
func (conn *Conn) tryAuth(m Auth, state authState, in *bufio.Reader) (error, bool) {
for {
s, err := authReadLine(in)
if err != nil {
return err, false
}
switch {
case state == waitingForData && string(s[0]) == "DATA":
if len(s) != 2 {
err = authWriteLine(conn.transport, []byte("ERROR"))
if err != nil {
return err, false
}
continue
}
data, status := m.HandleData(s[1])
switch status {
case AuthOk, AuthContinue:
if len(data) != 0 {
err = authWriteLine(conn.transport, []byte("DATA"), data)
if err != nil {
return err, false
}
}
if status == AuthOk {
state = waitingForOk
}
case AuthError:
err = authWriteLine(conn.transport, []byte("ERROR"))
if err != nil {
return err, false
}
}
case state == waitingForData && string(s[0]) == "REJECTED":
return nil, false
case state == waitingForData && string(s[0]) == "ERROR":
err = authWriteLine(conn.transport, []byte("CANCEL"))
if err != nil {
return err, false
}
state = waitingForReject
case state == waitingForData && string(s[0]) == "OK":
if len(s) != 2 {
err = authWriteLine(conn.transport, []byte("CANCEL"))
if err != nil {
return err, false
}
state = waitingForReject
}
conn.uuid = string(s[1])
return nil, true
case state == waitingForData:
err = authWriteLine(conn.transport, []byte("ERROR"))
if err != nil {
return err, false
}
case state == waitingForOk && string(s[0]) == "OK":
if len(s) != 2 {
err = authWriteLine(conn.transport, []byte("CANCEL"))
if err != nil {
return err, false
}
state = waitingForReject
}
conn.uuid = string(s[1])
return nil, true
case state == waitingForOk && string(s[0]) == "REJECTED":
return nil, false
case state == waitingForOk && (string(s[0]) == "DATA" ||
string(s[0]) == "ERROR"):
err = authWriteLine(conn.transport, []byte("CANCEL"))
if err != nil {
return err, false
}
state = waitingForReject
case state == waitingForOk:
err = authWriteLine(conn.transport, []byte("ERROR"))
if err != nil {
return err, false
}
case state == waitingForReject && string(s[0]) == "REJECTED":
return nil, false
case state == waitingForReject:
return errors.New("dbus: authentication protocol error"), false
default:
panic("dbus: invalid auth state")
}
}
}
// authReadLine reads a line and separates it into its fields.
func authReadLine(in *bufio.Reader) ([][]byte, error) {
data, err := in.ReadBytes('\n')
if err != nil {
return nil, err
}
data = bytes.TrimSuffix(data, []byte("\r\n"))
return bytes.Split(data, []byte{' '}), nil
}
// authWriteLine writes the given line in the authentication protocol format
// (elements of data separated by a " " and terminated by "\r\n").
func authWriteLine(out io.Writer, data ...[]byte) error {
buf := make([]byte, 0)
for i, v := range data {
buf = append(buf, v...)
if i != len(data)-1 {
buf = append(buf, ' ')
}
}
buf = append(buf, '\r')
buf = append(buf, '\n')
n, err := out.Write(buf)
if err != nil {
return err
}
if n != len(buf) {
return io.ErrUnexpectedEOF
}
return nil
}